Carl

The Shade spared him.

Hold up. Rewind.

You see, he worked for Nexus before its fall. He hid when Dr. Christoff came rampaging through the Science Tower, and was spared the Imperial's wrath. He watched the city's steady decline in the absence of Nexus's governance, and wondered when its continued facade would end.

He watched the occasional escaped Shade-beast (or just beast, sometimes) rampage through the city, and he was caught in the warpath of one of these creatures. And it should've ended there- but it didn't.

The Shade spared him.

He did not know what it meant until he found Dr. Crackpot. He'd never worked in Crackpot's department back in Nexus, but that didn't matter, because Crackpot welcomed him all the same- and Crackpot told him why he'd been spared.

He'd been spared because he'd never believed in rebuilding the city. Because he knew that this hope the residents still desperately clung onto was a sham. Because he knew that there was no point in prolonging the inevitable- the city's eventual collapse.

It was the first clarity he had had since the collapse. It was renewed purpose, too, a final answer as to why he still lived in a city that did not.

Following Crackpot into the chasms, Carl became a prophet to spread the word of what he now knew.